<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style>
div{margin:10px;
float:left}
#div1{width:50px;height:50px;background:red;}
#div2{width:180px;height:120px;background:#ccc;display:none;}
</style>
<script>
window.onload=function()
{
	var oDiv1=document.getElementById('div1');
	var oDiv2=document.getElementById('div2');
	var timer=null;//为定时器取个名，方便开关
	//合并相似代码
	oDiv2.onmouseover=oDiv1.onmouseover=function()//可以这样合并
	{
		clearTimeout(timer);//作用：关闭定时器,就是我
		oDiv2.style.display='block';
	}
	/*
	oDiv2.onmouseover=function()
	{
		clearTimeout(timer);
	}
	*/
	oDiv2.onmouseout=oDiv1.onmouseout=function()
	{
		timer=setTimeout(function(){
			oDiv2.style.display='none';
		},500);
	}
	
	/*
	oDiv2.onmouseout=function()
	{
		timer=setTimeout(function(){
			oDiv2.style.display='none';
		},500);//在这,上面写了一句话，是关于我
	}
	*/
}
</script>
</head>

<body>
<div id="div1"></div>
<div id="div2"></div>

</body>
</html>
